It sounds like Congressmen and Senators will make poor guests on TV and radio, since they cannot be "questioned" on the legislation they're considering. If that is what this means...
It looks like the context of Article I, Section 6, is affording congressmen and senators immunity from arrest for anything they do or say while in session.We are free to criticize anything our elected representatives say or do in a free debate.
I wasn’t being serious—I know we are free to question our representatives. Of course, Nancy Pelosi will call us Nazis if we do, but that’s another matter.